Preparation and thermogenic performance of monodisperse ferromagnetic Fe/SiO2 nanoparticles for magnetic hyperthermia and thermal ablation*

Abstract

Ferromagnetic nanoparticles have great potential to be used in the field of magnetic hyperthermia and thermal ablation due to its high saturation magnetization (Ms) and high heating efficiency. In this paper, monodisperse spherical α-Fe2O3 nanoparticles were prepared by hydrothermal method using FeCl3, NaHCO3 and Na2SO4 as reactants. Then monodisperse Fe/SiO2 nanoparticles with core/shell structure were obtained by coating SiO2 on the surface of α-Fe2O3 nanoparticles and reducing at 500℃ in hydrogen atmosphere. The diameter of Fe core is about 230 nm and the thickness of SiO2 coating is about 75 nm. Magnetic measurements show that Fe/SiO2 nanoparticles exhibit typical ferromagnetic properties with Ms about 132.5 emu/g at 25 ℃. As-obtained Fe/SiO2 nanoparticles have higher heating efficiency than superparamagnetic ferrite nanoparticles. The high heating ability of the Fe/SiO2 nanoparticles is estimated to be related to the hysteresis loss and Brownian relaxation mechanism during alternating magnetization. The results show that Fe/SiO2 nanoparticles are promising for the applications of magnetic hyperthermia and thermal ablation.